/**
 * #      1617
 * 名称   统计子树中城市之间最大距离
 * 链接   https://leetcode-cn.com/problems/count-subtrees-with-max-distance-between-cities
 * 题解   [28](https://leetcode-cn.com/problems/count-subtrees-with-max-distance-between-cities/solution)
 * 通过率 60.5%
 * 难道   困难
 */

